The present invention is related to the field of optical switches and, more particularly, to optical switches in which the switching function is effected by electromechanical devices.
In a 1XN optical switch, a single optical fiber forms an optical path with an optical fiber selected from N optical fibers. Thus a signal on the single optical fiber is transmitted to the selected fiber. Similarly a signal on the selected fiber is passed to the single optical fiber. A switch allows the optical connection to be changed from the selected fiber to another of the N fibers.
In electromechanical 1XN optical switches, the switching operation is effected by the movement of an end of the single optical fiber relative to the ends of the N optical fibers. To form an optical path, the end of the single optical fiber is aligned with the end of the selected fiber from the N fibers. In such systems alignment of the fiber ends is critical and much precision is required with the electromechanical drive devices, such as motors and their movements, to ensure accurate and reproducible alignment of the single fiber with each of the N optical fibers. Nonetheless, performance of such switches has remained poor with use restricted to multimode optical fibers. In present day optical networks it is often desirable to use single mode optical fibers.
A successful optical switch is disclosed in U.S. Pat. No. 5,359,683, which issued Oct. 25, 1994 and assigned to the present assignee. In this design GRIN lenses ameliorate the precise requirements of a mechanical alignment between optical fiber ends. Nonetheless, the disclosed optical switches are fairly expensive to manufacture. Stepper motors are required with GRIN lenses for each of the optical fibers in the switch and the size of the optical switch is relatively large which makes easy installation and hermetic sealing of the switch difficult.
The present invention addresses these shortcomings with a 1XN electromechanical optical switch which has not only high optical performance, but which is manufactured with relatively simple elements. The optical switch also is miniaturized for easy installation, easy hermetic sealing and resistance against shock.